Merge branch 'jn/fast-import-blob-access'
[git] / builtin / diff.c
1 /*
2  * Builtin "git diff"
3  *
4  * Copyright (c) 2006 Junio C Hamano
5  */
6 #include "cache.h"
7 #include "color.h"
8 #include "commit.h"
9 #include "blob.h"
10 #include "tag.h"
11 #include "diff.h"
12 #include "diffcore.h"
13 #include "revision.h"
14 #include "log-tree.h"
15 #include "builtin.h"
16 #include "submodule.h"
17
18 struct blobinfo {
19         unsigned char sha1[20];
20         const char *name;
21         unsigned mode;
22 };
23
24 static const char builtin_diff_usage[] =
25 "git diff [<options>] [<commit> [<commit>]] [--] [<path>...]";
26
27 static void stuff_change(struct diff_options *opt,
28                          unsigned old_mode, unsigned new_mode,
29                          const unsigned char *old_sha1,
30                          const unsigned char *new_sha1,
31                          const char *old_name,
32                          const char *new_name)
33 {
34         struct diff_filespec *one, *two;
35
36         if (!is_null_sha1(old_sha1) && !is_null_sha1(new_sha1) &&
37             !hashcmp(old_sha1, new_sha1) && (old_mode == new_mode))
38                 return;
39
40         if (DIFF_OPT_TST(opt, REVERSE_DIFF)) {
41                 unsigned tmp;
42                 const unsigned char *tmp_u;
43                 const char *tmp_c;
44                 tmp = old_mode; old_mode = new_mode; new_mode = tmp;
45                 tmp_u = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_u;
46                 tmp_c = old_name; old_name = new_name; new_name = tmp_c;
47         }
48
49         if (opt->prefix &&
50             (strncmp(old_name, opt->prefix, opt->prefix_length) ||
51              strncmp(new_name, opt->prefix, opt->prefix_length)))
52                 return;
53
54         one = alloc_filespec(old_name);
55         two = alloc_filespec(new_name);
56         fill_filespec(one, old_sha1, old_mode);
57         fill_filespec(two, new_sha1, new_mode);
58
59         diff_queue(&diff_queued_diff, one, two);
60 }
61
62 static int builtin_diff_b_f(struct rev_info *revs,
63                             int argc, const char **argv,
64                             struct blobinfo *blob,
65                             const char *path)
66 {
67         /* Blob vs file in the working tree*/
68         struct stat st;
69
70         if (argc > 1)
71                 usage(builtin_diff_usage);
72
73         if (lstat(path, &st))
74                 die_errno("failed to stat '%s'", path);
75         if (!(S_ISREG(st.st_mode) || S_ISLNK(st.st_mode)))
76                 die("'%s': not a regular file or symlink", path);
77
78         diff_set_mnemonic_prefix(&revs->diffopt, "o/", "w/");
79
80         if (blob[0].mode == S_IFINVALID)
81                 blob[0].mode = canon_mode(st.st_mode);
82
83         stuff_change(&revs->diffopt,
84                      blob[0].mode, canon_mode(st.st_mode),
85                      blob[0].sha1, null_sha1,
86                      path, path);
87         diffcore_std(&revs->diffopt);
88         diff_flush(&revs->diffopt);
89         return 0;
90 }
91
92 static int builtin_diff_blobs(struct rev_info *revs,
93                               int argc, const char **argv,
94                               struct blobinfo *blob)
95 {
96         unsigned mode = canon_mode(S_IFREG | 0644);
97
98         if (argc > 1)
99                 usage(builtin_diff_usage);
100
101         if (blob[0].mode == S_IFINVALID)
102                 blob[0].mode = mode;
103
104         if (blob[1].mode == S_IFINVALID)
105                 blob[1].mode = mode;
106
107         stuff_change(&revs->diffopt,
108                      blob[0].mode, blob[1].mode,
109                      blob[0].sha1, blob[1].sha1,
110                      blob[0].name, blob[1].name);
111         diffcore_std(&revs->diffopt);
112         diff_flush(&revs->diffopt);
113         return 0;
114 }
115
116 static int builtin_diff_index(struct rev_info *revs,
117                               int argc, const char **argv)
118 {
119         int cached = 0;
120         while (1 < argc) {
121                 const char *arg = argv[1];
122                 if (!strcmp(arg, "--cached") || !strcmp(arg, "--staged"))
123                         cached = 1;
124                 else
125                         usage(builtin_diff_usage);
126                 argv++; argc--;
127         }
128         if (!cached)
129                 setup_work_tree();
130         /*
131          * Make sure there is one revision (i.e. pending object),
132          * and there is no revision filtering parameters.
133          */
134         if (revs->pending.nr != 1 ||
135             revs->max_count != -1 || revs->min_age != -1 ||
136             revs->max_age != -1)
137                 usage(builtin_diff_usage);
138         if (read_cache_preload(revs->diffopt.paths) < 0) {
139                 perror("read_cache_preload");
140                 return -1;
141         }
142         return run_diff_index(revs, cached);
143 }
144
145 static int builtin_diff_tree(struct rev_info *revs,
146                              int argc, const char **argv,
147                              struct object_array_entry *ent)
148 {
149         const unsigned char *(sha1[2]);
150         int swap = 0;
151
152         if (argc > 1)
153                 usage(builtin_diff_usage);
154
155         /* We saw two trees, ent[0] and ent[1].
156          * if ent[1] is uninteresting, they are swapped
157          */
158         if (ent[1].item->flags & UNINTERESTING)
159                 swap = 1;
160         sha1[swap] = ent[0].item->sha1;
161         sha1[1-swap] = ent[1].item->sha1;
162         diff_tree_sha1(sha1[0], sha1[1], "", &revs->diffopt);
163         log_tree_diff_flush(revs);
164         return 0;
165 }
166
167 static int builtin_diff_combined(struct rev_info *revs,
168                                  int argc, const char **argv,
169                                  struct object_array_entry *ent,
170                                  int ents)
171 {
172         const unsigned char (*parent)[20];
173         int i;
174
175         if (argc > 1)
176                 usage(builtin_diff_usage);
177
178         if (!revs->dense_combined_merges && !revs->combine_merges)
179                 revs->dense_combined_merges = revs->combine_merges = 1;
180         parent = xmalloc(ents * sizeof(*parent));
181         for (i = 0; i < ents; i++)
182                 hashcpy((unsigned char *)(parent + i), ent[i].item->sha1);
183         diff_tree_combined(parent[0], parent + 1, ents - 1,
184                            revs->dense_combined_merges, revs);
185         return 0;
186 }
187
188 static void refresh_index_quietly(void)
189 {
190         struct lock_file *lock_file;
191         int fd;
192
193         lock_file = xcalloc(1, sizeof(struct lock_file));
194         fd = hold_locked_index(lock_file, 0);
195         if (fd < 0)
196                 return;
197         discard_cache();
198         read_cache();
199         refresh_cache(REFRESH_QUIET|REFRESH_UNMERGED);
200
201         if (active_cache_changed &&
202             !write_cache(fd, active_cache, active_nr))
203                 commit_locked_index(lock_file);
204
205         rollback_lock_file(lock_file);
206 }
207
208 static int builtin_diff_files(struct rev_info *revs, int argc, const char **argv)
209 {
210         int result;
211         unsigned int options = 0;
212
213         while (1 < argc && argv[1][0] == '-') {
214                 if (!strcmp(argv[1], "--base"))
215                         revs->max_count = 1;
216                 else if (!strcmp(argv[1], "--ours"))
217                         revs->max_count = 2;
218                 else if (!strcmp(argv[1], "--theirs"))
219                         revs->max_count = 3;
220                 else if (!strcmp(argv[1], "-q"))
221                         options |= DIFF_SILENT_ON_REMOVED;
222                 else if (!strcmp(argv[1], "-h"))
223                         usage(builtin_diff_usage);
224                 else
225                         return error("invalid option: %s", argv[1]);
226                 argv++; argc--;
227         }
228
229         /*
230          * "diff --base" should not combine merges because it was not
231          * asked to.  "diff -c" should not densify (if the user wants
232          * dense one, --cc can be explicitly asked for, or just rely
233          * on the default).
234          */
235         if (revs->max_count == -1 && !revs->combine_merges &&
236             (revs->diffopt.output_format & DIFF_FORMAT_PATCH))
237                 revs->combine_merges = revs->dense_combined_merges = 1;
238
239         setup_work_tree();
240         if (read_cache_preload(revs->diffopt.paths) < 0) {
241                 perror("read_cache_preload");
242                 return -1;
243         }
244         result = run_diff_files(revs, options);
245         return diff_result_code(&revs->diffopt, result);
246 }
247
248 int cmd_diff(int argc, const char **argv, const char *prefix)
249 {
250         int i;
251         struct rev_info rev;
252         struct object_array_entry ent[100];
253         int ents = 0, blobs = 0, paths = 0;
254         const char *path = NULL;
255         struct blobinfo blob[2];
256         int nongit;
257         int result = 0;
258
259         /*
260          * We could get N tree-ish in the rev.pending_objects list.
261          * Also there could be M blobs there, and P pathspecs.
262          *
263          * N=0, M=0:
264          *      cache vs files (diff-files)
265          * N=0, M=2:
266          *      compare two random blobs.  P must be zero.
267          * N=0, M=1, P=1:
268          *      compare a blob with a working tree file.
269          *
270          * N=1, M=0:
271          *      tree vs cache (diff-index --cached)
272          *
273          * N=2, M=0:
274          *      tree vs tree (diff-tree)
275          *
276          * N=0, M=0, P=2:
277          *      compare two filesystem entities (aka --no-index).
278          *
279          * Other cases are errors.
280          */
281
282         prefix = setup_git_directory_gently(&nongit);
283         gitmodules_config();
284         git_config(git_diff_ui_config, NULL);
285
286         if (diff_use_color_default == -1)
287                 diff_use_color_default = git_use_color_default;
288
289         init_revisions(&rev, prefix);
290
291         /* If this is a no-index diff, just run it and exit there. */
292         diff_no_index(&rev, argc, argv, nongit, prefix);
293
294         /* Otherwise, we are doing the usual "git" diff */
295         rev.diffopt.skip_stat_unmatch = !!diff_auto_refresh_index;
296
297         /* Default to let external and textconv be used */
298         DIFF_OPT_SET(&rev.diffopt, ALLOW_EXTERNAL);
299         DIFF_OPT_SET(&rev.diffopt, ALLOW_TEXTCONV);
300
301         if (nongit)
302                 die("Not a git repository");
303         argc = setup_revisions(argc, argv, &rev, NULL);
304         if (!rev.diffopt.output_format) {
305                 rev.diffopt.output_format = DIFF_FORMAT_PATCH;
306                 if (diff_setup_done(&rev.diffopt) < 0)
307                         die("diff_setup_done failed");
308         }
309
310         DIFF_OPT_SET(&rev.diffopt, RECURSIVE);
311
312         /*
313          * If the user asked for our exit code then don't start a
314          * pager or we would end up reporting its exit code instead.
315          */
316         if (!DIFF_OPT_TST(&rev.diffopt, EXIT_WITH_STATUS) &&
317             check_pager_config("diff") != 0)
318                 setup_pager();
319
320         /*
321          * Do we have --cached and not have a pending object, then
322          * default to HEAD by hand.  Eek.
323          */
324         if (!rev.pending.nr) {
325                 int i;
326                 for (i = 1; i < argc; i++) {
327                         const char *arg = argv[i];
328                         if (!strcmp(arg, "--"))
329                                 break;
330                         else if (!strcmp(arg, "--cached") ||
331                                  !strcmp(arg, "--staged")) {
332                                 add_head_to_pending(&rev);
333                                 if (!rev.pending.nr)
334                                         die("No HEAD commit to compare with (yet)");
335                                 break;
336                         }
337                 }
338         }
339
340         for (i = 0; i < rev.pending.nr; i++) {
341                 struct object_array_entry *list = rev.pending.objects+i;
342                 struct object *obj = list->item;
343                 const char *name = list->name;
344                 int flags = (obj->flags & UNINTERESTING);
345                 if (!obj->parsed)
346                         obj = parse_object(obj->sha1);
347                 obj = deref_tag(obj, NULL, 0);
348                 if (!obj)
349                         die("invalid object '%s' given.", name);
350                 if (obj->type == OBJ_COMMIT)
351                         obj = &((struct commit *)obj)->tree->object;
352                 if (obj->type == OBJ_TREE) {
353                         if (ARRAY_SIZE(ent) <= ents)
354                                 die("more than %d trees given: '%s'",
355                                     (int) ARRAY_SIZE(ent), name);
356                         obj->flags |= flags;
357                         ent[ents].item = obj;
358                         ent[ents].name = name;
359                         ents++;
360                         continue;
361                 }
362                 if (obj->type == OBJ_BLOB) {
363                         if (2 <= blobs)
364                                 die("more than two blobs given: '%s'", name);
365                         hashcpy(blob[blobs].sha1, obj->sha1);
366                         blob[blobs].name = name;
367                         blob[blobs].mode = list->mode;
368                         blobs++;
369                         continue;
370
371                 }
372                 die("unhandled object '%s' given.", name);
373         }
374         if (rev.prune_data) {
375                 const char **pathspec = rev.prune_data;
376                 while (*pathspec) {
377                         if (!path)
378                                 path = *pathspec;
379                         paths++;
380                         pathspec++;
381                 }
382         }
383
384         /*
385          * Now, do the arguments look reasonable?
386          */
387         if (!ents) {
388                 switch (blobs) {
389                 case 0:
390                         result = builtin_diff_files(&rev, argc, argv);
391                         break;
392                 case 1:
393                         if (paths != 1)
394                                 usage(builtin_diff_usage);
395                         result = builtin_diff_b_f(&rev, argc, argv, blob, path);
396                         break;
397                 case 2:
398                         if (paths)
399                                 usage(builtin_diff_usage);
400                         result = builtin_diff_blobs(&rev, argc, argv, blob);
401                         break;
402                 default:
403                         usage(builtin_diff_usage);
404                 }
405         }
406         else if (blobs)
407                 usage(builtin_diff_usage);
408         else if (ents == 1)
409                 result = builtin_diff_index(&rev, argc, argv);
410         else if (ents == 2)
411                 result = builtin_diff_tree(&rev, argc, argv, ent);
412         else if (ent[0].item->flags & UNINTERESTING) {
413                 /*
414                  * diff A...B where there is at least one merge base
415                  * between A and B.  We have ent[0] == merge-base,
416                  * ent[ents-2] == A, and ent[ents-1] == B.  Show diff
417                  * between the base and B.  Note that we pick one
418                  * merge base at random if there are more than one.
419                  */
420                 ent[1] = ent[ents-1];
421                 result = builtin_diff_tree(&rev, argc, argv, ent);
422         } else
423                 result = builtin_diff_combined(&rev, argc, argv,
424                                                ent, ents);
425         result = diff_result_code(&rev.diffopt, result);
426         if (1 < rev.diffopt.skip_stat_unmatch)
427                 refresh_index_quietly();
428         return result;
429 }